Speaker shock absorbers

From time to time people have posted different methods for mechanically decoupling their speakers from the floor to reduce vibration. Some of these have involved using a ply system of rubber strips and wood strips, which seems reasonable to me. I have looked for suitable sized sections of rubber or even for large sheets to cut up but have been unsuccessful. To those who have used that method -where did you find the material and what thickness of rubber and wood did you use for each layer - finally how many layers did you end up using?
Interesting thread.

My 150 lb speakers are on spike, but instead of sitting on carpet directly I found the sound to be better sitting on a 1/2" granite between spike and carpet. I used the granite which was left over from my house remodel for ease of moving the speakers initially, but after hearing what they do I left them under the speakers.

I am ready to try something like Symposium platform under the speakers, but I agree spikes should still be used regardless what you put under.
This is a bit older thread, but I thought I'd report some successful findings.

A few months ago I aquired a pair of Soliloquy 5.3i floorstanders. Great speakers! I'd been trying several types of footers to get the best balance, musicality, clarity, and bass.
With my older Soliloquy monitors it was no contest. Vibrapods hands down for clarity and great tone, exceptional liveliness, and even a little bass boost and growl.
With the floorstanders I tried several variations of vibrapods, different configurations and ratings (#4's and #5's). I got the clarity, tone and musicality I wanted, but the bass was always just a step behind the music and a little sloppy.
Another product I'd tried with the monitors are a cork and rubber product called Isol-Pads available here on Audiogon. They did a good job of decoupling the monitors but lightened the bass unacceptably. On the floorstanders however they have been great! Clarity is still good, the sound is very clean and musical and now the PRAT is back. Bass is appropriately quick and even, and still with satisfying weight. Low level liveliness is good, much better than on spikes, but not quite up to the more energy preserving vibrapods.
I would encourage anyone who wants to try decoupling their floorstanders to try the Isol-pad product. They are not at all expensive.

I have never tried these, but...Meade and other telescope manufacturers make isolation pads designed to go under tripod feet, sold in 3 piece sets.
Lots of industrial isolation pads available if you google.